Adult male rats receiving a single i.p. injection of chlordecone (Kepone) (80 mg/kg) exhibited a decreased (3H)GABA binding in frozen cerebellar and hippocampal membranes whereas the binding of (3H)-flunitrazepam to cerebellar membranes was unaffected. The binding of (3H)-mianserin was also depressed in hippocampal membranes whereas the (3H)-imipramine binding was unaffected in any area studied. It is hypothesized that the study of alterations in cerebral high-affinity binding sites may be a useful tool to detect cerebral changes caused by Kepone.